You need to move into the VW "Community" and you will learn everything you need to know. I had a 72 bug a few years ago and I think this was the forum I use to visit. VWVortex.com - Air-cooled
That is one of the most simple motors ever, it won't take long to get with it. I think that is a hot rod distributor most everyone uses them, I remember a name something like 006 or something like that,but I think that is what it is. Unless you are going to change a ring or something knowing the exact displacement isn't important, it's a "1600" pretty much. The carbs and intakes are aftermarket, no big deal. Really, don't over think it, this is simplicity at it's finest.